Commit c88ad30e authored by Mario Limonciello's avatar Mario Limonciello Committed by Rafael J. Wysocki
Browse files

cpufreq: amd-pstate: Add a kernel config option to set default mode 

Users are having more success with amd-pstate since the introduction
of EPP and Guided modes.  To expose the driver to more users by default
introduce a kernel configuration option for setting the default mode.

Users can use an integer to map out which default mode they want to use
in lieu of a kernel command line option.

This will default to EPP, but only if:
 1) The CPU supports an MSR.
 2) The system profile is identified
 3) The system profile is identified as a non-server by the FADT.

Link: https://gitlab.freedesktop.org/hadess/power-profiles-daemon/-/merge_requests/121


Acked-by: default avatarHuang Rui <ray.huang@amd.com>
Reviewed-by: default avatarGautham R. Shenoy <gautham.shenoy@amd.com>
Co-developed-by: default avatarPerry Yuan <perry.yuan@amd.com>
Signed-off-by: default avatarPerry Yuan <perry.yuan@amd.com>
Signed-off-by: default avatarMario Limonciello <mario.limonciello@amd.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 32f80b9a

drivers/cpufreq/Kconfig.x86

+17 −0
Original line number Diff line number Diff line
@@ -51,6 +51,23 @@ config X86_AMD_PSTATE 


	  If in doubt, say N.



config X86_AMD_PSTATE_DEFAULT_MODE

	int "AMD Processor P-State default mode"

	depends on X86_AMD_PSTATE

	default 3 if X86_AMD_PSTATE

	range 1 4

	help

	  Select the default mode the amd-pstate driver will use on

	  supported hardware.

	  The value set has the following meanings:

		1 -> Disabled

		2 -> Passive

		3 -> Active (EPP)

		4 -> Guided



	  For details, take a look at:

	  <file:Documentation/admin-guide/pm/amd-pstate.rst>.



config X86_AMD_PSTATE_UT

	tristate "selftest for AMD Processor P-State driver"

	depends on X86 && ACPI_PROCESSOR

drivers/cpufreq/amd-pstate.c

+48 −25
Original line number Diff line number Diff line
@@ -62,7 +62,7 @@ 
static struct cpufreq_driver *current_pstate_driver;

static struct cpufreq_driver amd_pstate_driver;

static struct cpufreq_driver amd_pstate_epp_driver;

static int cppc_state = AMD_PSTATE_DISABLE;

static int cppc_state = AMD_PSTATE_UNDEFINED;

static bool cppc_enabled;



/*
@@ -1410,6 +1410,25 @@ static struct cpufreq_driver amd_pstate_epp_driver = { 
	.attr		= amd_pstate_epp_attr,

};



static int __init amd_pstate_set_driver(int mode_idx)

{

	if (mode_idx >= AMD_PSTATE_DISABLE && mode_idx < AMD_PSTATE_MAX) {

		cppc_state = mode_idx;

		if (cppc_state == AMD_PSTATE_DISABLE)

			pr_info("driver is explicitly disabled\n");



		if (cppc_state == AMD_PSTATE_ACTIVE)

			current_pstate_driver = &amd_pstate_epp_driver;



		if (cppc_state == AMD_PSTATE_PASSIVE || cppc_state == AMD_PSTATE_GUIDED)

			current_pstate_driver = &amd_pstate_driver;



		return 0;

	}



	return -EINVAL;

}



static int __init amd_pstate_init(void)

{

	struct device *dev_root;
@@ -1417,15 +1436,6 @@ static int __init amd_pstate_init(void) 


	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)

		return -ENODEV;

	/*

	 * by default the pstate driver is disabled to load

	 * enable the amd_pstate passive mode driver explicitly

	 * with amd_pstate=passive or other modes in kernel command line

	 */

	if (cppc_state == AMD_PSTATE_DISABLE) {

		pr_info("driver load is disabled, boot with specific mode to enable this\n");

		return -ENODEV;

	}



	if (!acpi_cpc_valid()) {

		pr_warn_once("the _CPC object is not present in SBIOS or ACPI disabled\n");
@@ -1436,6 +1446,33 @@ static int __init amd_pstate_init(void) 
	if (cpufreq_get_current_driver())

		return -EEXIST;



	switch (cppc_state) {

	case AMD_PSTATE_UNDEFINED:

		/* Disable on the following configs by default:

		 * 1. Undefined platforms

		 * 2. Server platforms

		 * 3. Shared memory designs

		 */

		if (amd_pstate_acpi_pm_profile_undefined() ||

		    amd_pstate_acpi_pm_profile_server() ||

		    !boot_cpu_has(X86_FEATURE_CPPC)) {

			pr_info("driver load is disabled, boot with specific mode to enable this\n");

			return -ENODEV;

		}

		ret = amd_pstate_set_driver(CONFIG_X86_AMD_PSTATE_DEFAULT_MODE);

		if (ret)

			return ret;

		break;

	case AMD_PSTATE_DISABLE:

		return -ENODEV;

	case AMD_PSTATE_PASSIVE:

	case AMD_PSTATE_ACTIVE:

	case AMD_PSTATE_GUIDED:

		break;

	default:

		return -EINVAL;

	}



	/* capability check */

	if (boot_cpu_has(X86_FEATURE_CPPC)) {

		pr_debug("AMD CPPC MSR based functionality is supported\n");
@@ -1488,21 +1525,7 @@ static int __init amd_pstate_param(char *str) 
	size = strlen(str);

	mode_idx = get_mode_idx_from_str(str, size);



	if (mode_idx >= AMD_PSTATE_DISABLE && mode_idx < AMD_PSTATE_MAX) {

		cppc_state = mode_idx;

		if (cppc_state == AMD_PSTATE_DISABLE)

			pr_info("driver is explicitly disabled\n");



		if (cppc_state == AMD_PSTATE_ACTIVE)

			current_pstate_driver = &amd_pstate_epp_driver;



		if (cppc_state == AMD_PSTATE_PASSIVE || cppc_state == AMD_PSTATE_GUIDED)

			current_pstate_driver = &amd_pstate_driver;



		return 0;

	}



	return -EINVAL;

	return amd_pstate_set_driver(mode_idx);

}

early_param("amd_pstate", amd_pstate_param);

include/linux/amd-pstate.h

+3 −1
Original line number Diff line number Diff line
@@ -94,7 +94,8 @@ struct amd_cpudata { 
 * enum amd_pstate_mode - driver working mode of amd pstate

 */

enum amd_pstate_mode {

	AMD_PSTATE_DISABLE = 0,

	AMD_PSTATE_UNDEFINED = 0,

	AMD_PSTATE_DISABLE,

	AMD_PSTATE_PASSIVE,

	AMD_PSTATE_ACTIVE,

	AMD_PSTATE_GUIDED,
@@ -102,6 +103,7 @@ enum amd_pstate_mode { 
};



static const char * const amd_pstate_mode_string[] = {

	[AMD_PSTATE_UNDEFINED]   = "undefined",

	[AMD_PSTATE_DISABLE]     = "disable",

	[AMD_PSTATE_PASSIVE]     = "passive",

	[AMD_PSTATE_ACTIVE]      = "active",